For questions about the functionality related to permutations in Mathematica.

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14
votes
3answers
427 views

Generating Tuples with restrictions

I am interested in a certain subset of all tuples. Generating all with Tuples and then filtering is wasteful, and will "blow up" very quickly. For a concrete ...
13
votes
5answers
806 views

Permutations[Range[12]] produces an error instead of a list

This input: Permutations[Range[12]] Results in this (error) output: ...
13
votes
2answers
518 views

What is the fastest way to get the nth distinct permutation of a list?

What is the fastest way to write a function nthPermutation[xs_List, n_Integer] which is equivalent to Permutations[xs][[n]] but ...
12
votes
4answers
406 views

Equivalent Nested Loop Structure

Consider the following examples: ...
11
votes
4answers
1k views

How to remove repeated permutations?

I want to get the Permutations on the elements of a list. Then I'm doing this: ...
11
votes
6answers
456 views

Performing Computations on Sets

I would like to find a permutation of $\quad S=\{\frac{1}{10}, \frac{1}{2}, \frac{4}{7}, \frac{3}{5}, \frac{2}{3} \}\quad$ that maximizes the sum of theses elements raised to unique powers: ...
10
votes
3answers
260 views

Efficient way to turn a subset into a permutation

For an input vector $\{a_1,a_2,\ldots,a_n,b_{1},b_2,\ldots,b_{m}\}$ and a list of ordered positions $\{k_1,k_2,\ldots, k_n\}$, such that $1\leqslant k_1 < k_2 < \ldots < k_n \leqslant ...
10
votes
1answer
1k views

How to apply a permutation to a symmetric square matrix?

Given a symmetric square matrix, how can I apply a permutation to the rows and columns (i.e. the same permutation to both the rows and the columns) such a way that the new structure of the matrix ...
10
votes
1answer
301 views

Using Compile to speed up Function with PermutationProduct [closed]

I have the following fairly simple routine dot involving PermutationProduct that I wish to speed up using ...
9
votes
2answers
629 views

How to represent a list as a cycle

I want to select distinct cycles (represented by List). The cycle {a, b, c, d} must be the same as {b, c, d, a} or ...
9
votes
2answers
284 views

Combining nested lists that meet certain criteria for a permutation

I have the following list representing a permutation on 26 characters: ...
8
votes
6answers
2k views

Check if two lists are equal in any order

Suppose I have two lists, how can I efficiently check if the two lists are identical up to permutations of the elements? For example I would like the function to output: ...
8
votes
4answers
336 views

Using Permutations to create numbers

I'm a high school math teacher working on a simple high school math problem involving permutations. I like to try to check answers to some of these problems since it helps "convince" the students ...
8
votes
3answers
358 views

Reduce the output from tuples by including symmetry?

I need all the possible 3x3 binary tensors, but I'd like to have this account for symmetries. I've started by using the Tuples command. Tuples[{1, 0}, {3, 3}] ...
8
votes
1answer
479 views

Mathematica function/package for shuffle permutations

Does anyone knows a way to compute a list of all (p,q)-shuffles in mathematica? For a definition of the shuffle permutations see for example http://ncatlab.org/nlab/show/shuffle I'm dreaming of a ...
8
votes
1answer
96 views

Duplicate-free results of permutations + constant list

Given a constant list const, e.g. const = {-(15/2), -(13/2), -(17/2), -(15/2), -(13/2), -(11/2)} of length ...
8
votes
1answer
153 views

Equivalence under common permutations

I have lists which consists of sublists of equal length. The outer list is regarded as a multiset (that is, permutations of the sublists don't matter, but repetitions do), but the order in the ...
6
votes
2answers
408 views

Find all permutations with a condition

How can I find all the permutations of {a, b, c} where a + b + c = n? For instance: if ...
6
votes
3answers
240 views

How to get “Signature” of each element of “Permutation” output

I need to sum over all possible permutations, multiplied by the Signature of each permutation of a given list of symbols. But, I don't know how to determine the ...
6
votes
2answers
106 views

Nested permutations

I would like to compute all "nested permutations" (not sure if it's the right term) of a list consisting of simple elements (numbers, strings) and simple sublists (level 1 lists of simple elements). ...
6
votes
2answers
185 views

Challenge: Creating Compilable Permutations Function

As Mathematica's implemented Permutations function is not compilable I tried to write my very own Permutations implementation, called ...
6
votes
3answers
1k views

neighbor swapping distance between two strings

Updated Problem Description I have a collection of strings $S$ that only contain two (or $m$ in general) kinds of elements: in this case C and D. For all $s\in S$, the length is the same, the number ...
5
votes
4answers
287 views

How to split a list with respect to its nested sublists?

I have a problem with the following task: having some nested list list = {{k6},{k1,k3,k5},{k7}} I would like to replace all sublists by their permutations and ...
5
votes
4answers
542 views

How can I generate permutations of bit strings with repetition?

How can I write a function which has two parameters and it should generate combination of arbitrary range bits, for example: function[n, k], with ...
5
votes
4answers
221 views

Sort two lists at the same time, based on another

I am new to using Mathematica and I can not find a solution to what I am wanting to do. I want to take a list such as: x = {1,2,3,4,5,6,7,8} and a second list ...
5
votes
2answers
316 views

How to enumerate multisets?

Given the eight-element set {1,2,3,4,5,6,7,8}, I would like to enumerate all multisets (subsets with repetition) of size n, ...
5
votes
1answer
72 views

What does the Combinatorica function: NumberOfPermutationsByType return?

I am using Mathematica 9. If I input: NumberOfPermutationsByType[{2, 2, 1, 1}] Mathematica returns 1/8. I was expecting ...
5
votes
3answers
187 views

How to find the right permutation, which fits to the problem?

I'm new here and I hope I can find some help. I'm from Germany, so sorry for my English. I look for a number, whose digits are all different. It isn't known how many digits it has. But there is a ...
5
votes
1answer
103 views

How to get a new list by exchanging some elements?

Let's begin with a simple example. Now, we have a list, list0=Range[4]; k1 and k2 are some elements of the list0. If |k1-k2|==2, then the elements k1 and k2 can ...
5
votes
2answers
225 views

How to define even permutations correctly?

I define even permutations as following, but there may be some error. I use it in two different way and get different output. ...
5
votes
1answer
100 views

Finding the reduced permutations of six numbers

I am trying to use Mathematica to find the following set of permutations: $$\sum_{\rho\in \tilde{S}_{n+2}} {\rm sgn}(\rho)\eta^{\mu_{\rho_{(1)}}\mu_{\rho_{(2)}}} $$ where $$ ...
4
votes
3answers
191 views

Permutation count for sets with multiplicities

I am able to do a permutation counr for the set {a, a, b} which gives me 3 groups. I am happy with that result. However, if the set is ...
4
votes
2answers
161 views

Permutations: selecting reviewers without conflicts of interest

I would like to automate the process of selecting a number of proposal reviewers that fit a conflict of interest criterion. Let's say I have 5 reviewers and 5 applicants from 5 departments. The ...
4
votes
1answer
123 views

Permute list of strings

Say I have a list of strings like slist={"apple","123","Car"} What I want is a list of all permutations of slist. The result ...
4
votes
1answer
240 views

Help with Permutations

I am currently trying to generate a list of permutations of length 2 of elements of a list of strings. For example: ...
4
votes
1answer
61 views

How can I “permute” an ordered pair over all the permutations of say $S_4$?

I want to make an action table of the symmetric group (say $S_4$) acting on the set of unordered pairs of distinct vertices of a square. I have the list of such pairs: ...
3
votes
3answers
207 views

Permutations on elements a>b && b>c

A={1, 2, 3, 4, 5} Permutations[A, {3}] I need to print all permutations where the first number is bigger than the second and the second number is bigger than the ...
3
votes
3answers
178 views

Permutations of 0's and 1's in a lower-triangular matrix

For a given $n \ge 5$ create every $n$-by-$n$ matrix containing exactly four $1$'s strictly below the diagonal and $0$'s elsewhere.
3
votes
2answers
83 views

How can I filter a permutation list depending of a pattern? [closed]

I've created a permutation list Grid[Permutations[{a, e, q, r, t, u}], Frame -> All] and only want to see rows where the 5th element is a "t". I tried to do ...
3
votes
3answers
121 views
3
votes
4answers
210 views

How to merge permutations obtained from Solve on multiple variables?

When I compute the following expression to find integer solutions of the equation (x^2 + y^2 + z^2 == 14^2) ...
3
votes
2answers
91 views

Creating all permutations of list with “alignment”

I need to find all permutations of a list satisfying a condition but I'm lost about how to do so. Given a list I want a write a function to produce all permutations such that the list is "top aligned" ...
3
votes
2answers
285 views

Permuting elements within a list

I have s = {2, 3, 5, 7, 1, 4, 6} (* always with diffente elements in {1,2....7}*) l = Length[s] n = 3 and n tells us that we ...
3
votes
2answers
142 views

Generating permutations of at most 'n' elements, and where a specific subset of elements always appears

I often run into a situation where I'd like to generate a set of permutations with at most $n$ elements (here $n = 5$): ...
3
votes
1answer
107 views

How do I create a logical permutation expression automatically

How can I create a permutation automatically with logical expressions ? For example (2 logical variables): ...
3
votes
2answers
455 views

Need to create a function to generate all permutations of Range[$n$] [duplicate]

Basically I need a function that takes a list and gives all the possible permutations of it. The reason I can't use Permutations is that I have to apply another ...
2
votes
3answers
174 views

How can I get from a list of characters representing a permutation to graphics showing the cycles?

I am trying to graphically represent cycles in various permutations of the alphabet, and have a question in two parts. I have ...
2
votes
2answers
124 views

How to find the palindromic number I'm looking for?

I'm looking for a number which is the same when you read it reverse like 101 or 878. I have to get all numbers from 10 to 1000. There are 99 numbers. ...
2
votes
1answer
257 views

How can I permute a multiset?

I have a multiset {1, 3, 3, 1, 2} and would like to randomly permute the classes like so: {2, 1, 1, 2, 3} or {3, 2, 2, 3, 1}, what is the simplest and most efficient way to do this? In reality the ...
2
votes
1answer
538 views

Adding rules to permutations

How can I calculate only those permutations of Range[n], that satisfy certain rules? I don't want to filter the result after calculating all the permutations but ...